Codec output directory is hardcoded

Java codec generator assumes the codecs will be generated under the IMDG project and assumes its directory structure. We now require them to be generated under MC repository to be able to evolve the codecs independently from IMDG releases.

For this to work, we can follow either of the following two ways:

1. Make the following four lines to be configurable

https://github.com/hazelcast/hazelcast-client-protocol/blob/81b91c380c1bc790a5de4e7a50f5b3946468cf69/util.py#L202
https://github.com/hazelcast/hazelcast-client-protocol/blob/81b91c380c1bc790a5de4e7a50f5b3946468cf69/util.py#L211
https://github.com/hazelcast/hazelcast-client-protocol/blob/e7643355cbcd65c4145d1818893bffeab0177f8c/binary/util.py#L313
https://github.com/hazelcast/hazelcast-client-protocol/blob/e7643355cbcd65c4145d1818893bffeab0177f8c/binary/util.py#L322

2. Deduce the output directories automatically from the namespace argument (converting the package name to a directory structure, i.e. when `com.hazelcast.webmonitor.client.impl.protocol.codec` is passed, classes will be generated under `/src/main/java/com/hazelcast/webmonitor/client/impl/protocol/codec/`).